Soil

By: Nitin Goel
SOIL

What Is Soil?

Soil is one of the three major natural resources, alongside air and water. It is one of the marvellous products of nature and without which there would be no life.


Salinization is The condition in which the salt content of soil accumulates over time to above normal levels, it occurs in some parts of the world where water containing high salt concentration evaporates from fields irrigated with standing water.

Salinity in soil is caused by irrigating the crops by salty water during the evaporation the water from the soil evaporates leaving the soil behind causing salinization .
Salinization causes the soil structure to break down causing infertility and the plants cannot grow.
external image salinization_solodized_pr2_Agri_Food_Canada.jpg

Nutrient Depletion is reduction of essential nutrients ( through plant uptake and removal of plant residues, or through leaching) to a level at which they become unavailable for further uptake.


Soil pollution, also commonly referred to as soil contamination, is defined as a phenomenon characterized by the loss of structural and biological properties by the soil layers as a result of numerous human and natural factors, such as wind, deforestation, chemical use, among others.

Soil pollution is a result of many activities and experiments done by mankind and some of the leading soil pollution causes are discussed below.
  • Industrial wastes, such as harmful gases and chemicals, agricultural pesticides, fertilizers and insecticides are the most important causes of soil pollution.
  • Ignorance towards soil management and related systems.
  • Unfavorable and harmful irrigation practices.
  • Improper septic system and management and maintenance of the same.
  • Leakages from sanitary sewage.
  • Acid rains, when fumes released from industries get mixed with rains.
  • Fuel leakages from automobiles, that get washed away due to rain and seep into the nearby soil.
  • Unhealthy waste management techniques, which are characterized by release of sewage into the large dumping grounds and nearby streams or rivers.

Effects of Soil Pollution

The effects of pollution on soil are quite alarming and can cause huge disturbances in the ecological balance and health of living creatures on earth. Some of the most serious soil pollution effects are mentioned below.
  • Decrease in soil fertility and therefore decrease in the soil yield. Definitely, how can one expect a contaminated soil to produce healthy crops?
  • Loss of soil and natural nutrients present in it. Plants also would not thrive in such a soil, which would further result in soil erosion.
  • Disturbance in the balance of flora and fauna residing in the soil.
  • Increase in salinity of the soil, which therefore makes it unfit for vegetation, thus making it useless and barren.
  • Generally crops cannot grow and flourish in a polluted soil. Yet if some crops manage to grow, then those would be poisonous enough to cause serious health problems in people consuming them.

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external image soil-pollution.jpg


Soil organic matter


Soil organic matter (SOM) is the organic matter component of soil. It can be divided into three general pools: living biomass of microorganisms, fresh and partially decomposed residues, and humus: the well-decomposed organic matter and highly stable organic material



How Does SOM prevents soil degradation?
  • SOM helps soil to retain moisture, and dark color helps to retain heat and warm the soil during the spring.
  • It contains mineral nutrients that it exchanges with plants (at the roots).
  • it improves the soil structure
  • it reduces soil erosion.

Physical Functions of soil organic matter-
  • Bind soil particles together in stable aggregates
  • Influence water holding and aeration
  • Influence soil temperature

Biological Functions of soil organic matter-
  • Food source for microbes and small animals
  • Major reservoir of plant nutrients


The most common organic soil polluters are as follows-
Polynuclear aromatic hydrocarbons (PAHs)-Polynuclear aromatic hydrocarbons were used in tar as a preservative for wood in ships and buildings for centuries.
Oil and coal also contain polynuclear aromatic hydrocarbons.

Polychlorinated biphenyls (PCBs)-Polychlorinated biphenyls were added to paint and sealants, electrical installations and hydraulic oils because they were good fire retardants and plasticizers. Old buildings and electrical installations are still a source of PCBs.

Dioxins and furans, which are created by burning organic waste, are common

Phthalates, which are produced from the production of plastic and cement.

REFRENCES-
1.)Common Organic Soil Pollutants, Published On 2010, November 12,Retrived on April 3, 2011, Published By Linda Madso, http://www.ehow.com/list_7488155_common-organic-soil-pollutants.html

2.) Soil Organic Matter, Published On 2010,may 19, Retrived on April 6, 2011, Published by Department of Primary Industries, Parks, Water and Environment. http://www.dpiw.tas.gov.au/inter.nsf/WebPages/TPRY-5YW6YZ?open.

3.)Soil Organic matter, Published On May 30,2011, Retrived on April7 2011, Published by J. Lickacz and D. Penny, http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex890

4.) Soil Degradation, Published On 26 February 2011, Retrieved on 7th april 2011, Published by Office of environment and Heritage, http://www.environment.nsw.gov.au/soildegradation/index.htm